A partnership between the University of Iowa College of Public Health and the Institute for Agriculture and Trade Policy conducted the largest U.S. survey of retail meat. The study looked at nearly 400 samples of various pork products collected throughout supermarkets in Iowa, Minnesota and New Jersey. Nearly 7 percent of the samples contained detectable levels of MRSA. According to lead study author Tara Smith, Ph.D., interim director of the UI Center for Emerging and Infectious Diseases and assistant professor of epidemiology, “This study shows that the meat we buy in our grocery stores has a higher prevalence of staph than we originally thought.”

The study made another surprising discovery: There was no notable difference in the levels of MRSA contamination between conventionally raised pork products and those claiming to be raised without antibiotics or other drugs. “We were surprised to see no significant difference in antibiotic-free and conventionally produced pork,” said Smith.

Some 185,000 cases of food poisoning are caused by MRSA in the U.S. each year, and the bacteria, which are extremely difficult to treat because of resistance to antibiotics, can lead to life-threatening infections.

The study researchers hope that the findings will help lead to recommendations for safer handling methods of all raw meat products, not just for the end consumer, but also in slaughtering and processing the animals, where much of the contamination is believed to occur.